html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  /* 调整北京图片的三种方式 */
  background: url(../img/bg.jpg);
  background-repeat: no-repeat;
  background-size: 100% 100%;
  background-position: 0 0;
}

h3 {
  margin: 0;
}

a {
  /* 去掉下划线 */
  text-decoration: none;
}

div {
  box-sizing: border-box;
}

.mask {
  width: 100%;
  height: 100%;
  background-color: #000;
  opacity: 0.6;
}

#model {
  width: 450px;
  height: 350px;
  background-color: white;
  top: 0;
  left: 0;
  position: absolute;
  border-radius: 15px;
  overflow: hidden;
}

#model .model-hd {
  width: 100%;
  height: 50px;
  background-color: #4896dc;
  /* 十字图标 让用户明白可以拖动 */
  cursor: move;
  line-height: 50px;
  padding: 0 15px;
}

#model .model-hd h3 {
  display: inline;
  color: #fff;
}

#model .model-hd h3 i {
  color: #f1c747;
}

#model .model-hd a {
  float: right;
  color: #fff;
  margin-top: 18px;
}
